The art of book binding is centuries old, and vital to the flow and storage of information. It is constantly being improved, but is still limited by the number of steps necessary to asssemble, collate and secure signatures and turn the assembled signatures into a finished book, as well as by the comparative weakness of the binding of the finished book. For example, in case binding for hard-cover books, considerable hand labor, skill and expensive equipment are required to sew and glue collated signatures together. Conventional perfect adhesive binding for paperback books, while less expensive than case binding, has neither the same high quality appearance, nor the strength, as that of hard cover books.
Applicant's U.S. Pat. No. 4,091,487, issued May 30, 1978, for a "Method For Binding Books" discloses an important improvement over conventional book binding, wherein the signatures are first collated, and then the spines or backbones of the signatures are cut off to provide a single backbone exposing every sheet in every signature, and whose edges can be glued together and to at least one paper cover that will ultimately be glued to the interior surfaces of a conventional hard cover, after the other three edges of the assembled and collated signatures are trimmed.
Applicant's U.S. Pat. No. 4,106,148, issued Aug. 15, 1978, for a "Method of Binding Papers", discloses an additional improvement over conventional book binding, wherein notches or apertures are cut into the spines at intervals to permit the flow of adhesive glue well into the backbone of all of the pages in every signature. This method avoids the waste of paper and the extra step of grinding the backbone while still eliminating the even-more-costly step of sewing the signatures.
While the methods disclosed in the two above-identified patents are a considerable improvement over the more time-consuming and costly book binding systems of the prior art, such methods share the mechanical weakness of the prior ar book binding methods in that the signatures are fastened, by thread or glue, to a single central edge of a cover than can be relatively easily broken away from the binding. Thus, if the signatures are grasped in one hand, and the paper cover or the hard cover grasped in the other hand, the single, narrow bonding can be pulled apart relatively easily.